handysoft groupware arbitrary file download and execution vulnerability

published 2021-09-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13402

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits: 0; none known

An arbitrary file download and execution vulnerability was found in the HShell.dll of handysoft Co., Ltd groupware ActiveX module. This issue is due to missing support for integrity check of download URL or downloaded file hash.

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

handysoft HShell.dll

Classification

Weakness

CWE-353 Missing Support for Integrity Check
CWE-345 Insufficient Verification of Data Authenticity

References

boho.or.kr /krcert/secNoticeView.do?bulletin_writing_sequence=36239
third-party-advisory

Sources

CVE List CVE-2021-26608
NVD CVE-2021-26608

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Summary